HD44780::SR3W Class Reference

#include <HD44780.hh>

Inheritance diagram for HD44780::SR3W:

Collaboration diagram for HD44780::SR3W:

Classes
union	port_t

Public Member Functions
	SR3W (Board::DigitalPin sda=Board::D7, Board::DigitalPin scl=Board::D6, Board::DigitalPin en=Board::D5)
virtual bool	setup ()
virtual void	write4b (uint8_t data)
virtual void	write8b (uint8_t data)
virtual void	set_mode (uint8_t flag)
virtual void	set_backlight (uint8_t flag)
virtual void	write8n (const void *buf, size_t size)

Protected Attributes
port_t	m_port
	Port setting. More...
OutputPin	m_sda
	Serial data output. More...
OutputPin	m_scl
	Serial clock. More...
OutputPin	m_en
	Starts data read/write. More...

Static Protected Attributes
static const uint16_t	SHORT_EXEC_TIME = 20

Detailed Description

HD44780 (LCD-II) Dot Matix Liquid Crystal Display Controller/Driver Shift Register 3-Wire Port (SR3W), 74HC595/74HC164 (SR[pin]), with digital output pins.

Circuit

                        74HC595    (VCC)
                      +----U----+    |
(LCD D5)------------1-|Q1    VCC|-16-+
(LCD D6)------------2-|Q2     Q0|-15-----------(LCD D4)
(LCD D7)------------3-|Q3    SER|-14-----------(SDA/D7)
(LCD RS)------------4-|Q4    /OE|-13-----------(GND)
(LCD BT)------------5-|Q5   RCLK|-12-----------(EN/D5)
                    6-|Q6   SCLK|-11-----------(SCL/D6)
                    7-|Q7    /MR|-10-----------(VCC)
                  +-8-|GND   Q6'|--9
                  |   +---------+
                  |      0.1uF
                (GND)-----||----(VCC)
(LCD EN)---------------------------------------(EN/D5)
(LCD RW)---------------------------------------(GND)
(LCD K)----------------------------------------(GND)
(LCD A)-----------------[330]------------------(VCC)

Alternative circuit with 74HC164.

                        74HC164    (VCC)
                      +----U----+    |
(SDA/D7)----------+-1-|DSA   VCC|-14-+
                  +-2-|DSB    Q7|-13
(LCD D4)------------3-|Q0     Q6|-12
(LCD D5)------------4-|Q1     Q5|-11--------(LCD BT)
(LCD D6)------------5-|Q2     Q4|-10--------(LCD RS)
(LCD D7)------------6-|Q3    /MR|--9-----------(VCC)
                  +-7-|GND    CP|--8--------(SCL/D6)
                  |   +---------+
                  |      0.1uF
                (GND)-----||----(VCC)
(LCD EN)---------------------------------------(EN/D5)
(LCD RW)---------------------------------------(GND)
(LCD K)----------------------------------------(GND)
(LCD A)-----------------[330]------------------(VCC)

Performance

The LSB of the shift register is used to allow reduction of number of shift operations (i.e. 6-bit shift).

Definition at line 483 of file HD44780.hh.

Constructor & Destructor Documentation

HD44780::SR3W::SR3W	(	Board::DigitalPin	sda = Board::D7,
		Board::DigitalPin	scl = Board::D6,
		Board::DigitalPin	en = Board::D5
	)

Construct HD44780 3-wire serial port connected to given serial data, clock and enable pulse pin.

Parameters

[in]	sda	serial data pin (Default D7, Tiny/D1)
[in]	scl	serial clock pin (Default D6, Tiny/D2)
[in]	en	enable pulse (Default D5, Tiny/D3)

Definition at line 23 of file HD44780_SR3W.cpp.

Member Function Documentation

void HD44780::SR3W::set_backlight ( uint8_t  flag )

virtual

Set backlight on/off using bt pin.

Parameters

[in]

flag.

Implements HD44780::IO.

Definition at line 85 of file HD44780_SR3W.cpp.

void HD44780::SR3W::set_mode ( uint8_t  flag )

virtual

Set instruction/data mode using given rs pin; zero for instruction, non-zero for data mode.

Parameters

[in]

flag.

Implements HD44780::IO.

Definition at line 79 of file HD44780_SR3W.cpp.

bool HD44780::SR3W::setup ( )

virtual

Initiate serial port. Returns false.

Returns

bool.

Implements HD44780::IO.

Definition at line 34 of file HD44780_SR3W.cpp.

void HD44780::SR3W::write4b ( uint8_t  data )

virtual

Write LSB nibble to display using serial port.

Parameters

[in]

data

(4b) to write.

Implements HD44780::IO.

Definition at line 40 of file HD44780_SR3W.cpp.

void HD44780::SR3W::write8b ( uint8_t  data )

virtual

Write byte (8bit) to display.

Parameters

[in]

data

(8b) to write.

Reimplemented from HD44780::IO.

Definition at line 69 of file HD44780_SR3W.cpp.

void HD44780::IO::write8n ( const void *  buf, size_t  size  )

virtualinherited

Write character buffer to display.

Parameters

[in]	buf	pointer to buffer.
[in]	size	number of bytes in buffer.

Reimplemented in ERM1602_5, Adafruit_I2C_LCD_Backpack, DFRobot_IIC_LCD_Module, MJKDZ_LCD_Module, and SainSmart_LCD2004.

Definition at line 31 of file HD44780_IO.cpp.

Member Data Documentation

OutputPin HD44780::SR3W::m_en

protected

Starts data read/write.

Definition at line 564 of file HD44780.hh.

port_t HD44780::SR3W::m_port

protected

Port setting.

Definition at line 561 of file HD44780.hh.

OutputPin HD44780::SR3W::m_scl

protected

Serial clock.

Definition at line 563 of file HD44780.hh.

OutputPin HD44780::SR3W::m_sda

protected

Serial data output.

Definition at line 562 of file HD44780.hh.

const uint16_t HD44780::SR3W::SHORT_EXEC_TIME = 20

staticprotected

Execution time delay (us).

Definition at line 540 of file HD44780.hh.

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The documentation for this class was generated from the following files:

• libraries/HD44780/HD44780.hh
• libraries/HD44780/HD44780_SR3W.cpp